Why does the WPC door panel extruder control not use a PLC, while the cutting machine control does?

At Jiangsu Xinhe Intelligent Equipment, our automation-savvy customers sometimes ask: "If the cutter uses high-speed servo and PLC control, why does the main extruder rely on inverters and PID controllers?" The answer lies in application-specific engineering, using the right tool for the right job.

The Extruder: Stability Above All

The twin-screw extruder is a conical extruder that does continuous melting and mixing and conveying. It does not succeed by any elaborate logic sequencing, but by:

Precise temperature maintenance (within ±1°C) to protect wood fiber

Constant torque and speed in relation to variable back-pressure.

In such tasks dedicated components are superior to integrated systems. Our PID temperature zone controllers are of high quality as also are our ABB frequency inverters to provide screw speed control. These controllers are based on shorter response times in heating/cooling loops and are more resistant to high electric noise conditions. Whereas, a PLC is good in logic, pure analog process regulation is better realized with dedicated controllers.

The Cutter: Precision Above All

The moving cutter needs to align to the moving profile, speeding up, becoming matched, cutting neatly (within ±0.5mm tolerance) and returning, the line constantly moving.

This demands:

Complicated electronic gear ratios.

Encoded feedback responds instantly.

High-speed motion control

In this instance, a PLC and a Servo drive should be used. It does the cut timing logic, talks to the servo on how to make perfect synchronized cuts and makes the lengths consistent. It would not be possible to achieve this precision without the PLC control.

Reliability Through Simplicity

When using wood dust and heat, such as in the WPC processing, the direct correlation between uptime and simplicity is observed. Should we bring about all functions into one and big PLC:

One breakdown would close the whole line.

Complex software diagnostic would be necessary in troubleshooting.

With our distributed architecture, a faulty temperature sensor affects only one zone and can be easily replaced. The PLC-based cutter operates semi-independently. The PLC-based system of cutter is semi-independent. This modularity will make sure that minor issues will not lead to complete system shutdown.

The Xinhe Philosophy

On the extruder we are very concerned with stability in using inverters and using specific controllers to maintain the quality of melt. On the cutter, PLC and Servo systems are favored in order to have a burr-free edge and a minimum amount of wastage.

Every system is connected with each other through HMI touchscreen, allowing the operators to control the whole system and specialized components to perform their dedicated duties. This is not a technological constraint, it is optimization of the engineering through years of extrusion experience and customer opinions around Indonesia, Mexico and Vietnam and so on.

In selecting Xinhe you receive an embodiment of a production solution that is to work in the real world where the extruder works continuously like the heart, the cutter works like a hand reacts and the control philosophy appreciates both precision and industrial reliability.